Human hair varies greatly in character between individuals. Hair differs in thickness, texture, color and shape. A variety of products and methods have been developed to modify each of these characteristics. There are hair coloring products, hair conditioning products, hair cleansers and products to control the straightness or curliness of hair. This last category of hair products is the subject of the present invention.
Natural curly hair or frizzy hair frequently causes many hair styling problems. For example, the hair tends to spread uncontrollably, hair tips curl up, and/or it is difficult to be arranged tidily. A number of methods have been proposed for curing these problems of curly or frizzy hair. A typical cure is the so-called permanent straightening treatment, a chemical treatment which comprises fully cleaving disulfide bonds in hair keratin through a chemical reduction process and stretching the hair by adhering it to a panel or combing it. The straightened hair is then oxidized and fixed to restore the disulfide bonds in the hair, thereby permanently straightening the hair. The disadvantage of this approach is that the harsh chemicals used are an irritation to the scalp and skin due to the high pH (10-12) of the caustics or similar compounds. In addition, the hair cuticle is uplifted causing extensive damage which results in dry and dull hair from reduced sebum flow from the scalp. The structure of the hair is also permanently damaged because the chemical bonds in the hair fibers are broken and only some are reformed into new covalent bonds.
An alternative solution is the use of hair spray products. Hair spray products are applied to wet or dry hair and contain a polymer, or mixtures of polymers, that remain fixed on the previously styled hair. The film-forming polymers are used to provide a flexible sheath on the shaped hair after drying, and, therefore, for mechanical reasons, retard the return of each individual hair to its natural shape. In addition, the polymeric film provides an overall stiffening of the hair. The hair behaves as if the individual hair strands are welded together, and the final hairstyle has better cohesion, therefore, resisting the natural forces that return the hair to its natural shape. A disadvantage of the conventional hair sprays is that the polymer film is easily removed by a single shampoo requiring that the hair spray be reapplied. Additionally, polymer films lose their effectiveness to retain the style of the hair over time, especially when exposed to high relative humidity.
It is an object of the present invention to provide a composition that is able to straighten hair without the damaging disruption of chemical bonds in the hair and is also durable by remaining on the hair even after shampooing and exposure to high humidity.